are the VBA modules in one excel worksheet local to that sheet only?

Hello
I was looking at UDF which are embeeded in sheets. the excel file seems to have three worksheets whcih have been named as sheetA, SheetB, SheetC, SheetD, SheetE

when i look at the UDF functions by clicking (Alt+F11) then i five sheets each having a set of modules.

are the VBA modules in one sheet local to that sheet only?

A VBA module is public to the Workbook or .xls file.

so all the spreadsheets can access the UDF's in the module, correct?

Correct. If I remember correctly you can go like ... Book1.xls!MyFunction